diff --git a/apigee_edge.services.yml b/apigee_edge.services.yml
index 0582af15..bcee9b90 100644
--- a/apigee_edge.services.yml
+++ b/apigee_edge.services.yml
@@ -15,7 +15,7 @@ services:
 
   apigee_edge.sdk_connector:
     class: Drupal\apigee_edge\SDKConnector
-    arguments: ['@http_client_factory', '@key.repository', '@entity_type.manager', '@config.factory', '@module_handler', '@info_parser']
+    arguments: ['@http_client_factory', '@key.repository', '@config.factory', '@module_handler', '@info_parser']
 
   apigee_edge.key_entity_form_enhancer:
     class: Drupal\apigee_edge\KeyEntityFormEnhancer
diff --git a/modules/apigee_edge_debug/apigee_edge_debug.services.yml b/modules/apigee_edge_debug/apigee_edge_debug.services.yml
index 51d6c631..01ff15e6 100644
--- a/modules/apigee_edge_debug/apigee_edge_debug.services.yml
+++ b/modules/apigee_edge_debug/apigee_edge_debug.services.yml
@@ -8,7 +8,7 @@ services:
     decorates: apigee_edge.sdk_connector
     decoration_priority: -10
     public: false
-    arguments: ['@apigee_edge_debug.sdk_connector.inner', '@http_client_factory', '@key.repository', '@entity_type.manager',  '@config.factory', '@module_handler', '@info_parser']
+    arguments: ['@apigee_edge_debug.sdk_connector.inner']
     properties:
       # Without this property for decorated services, serialization will fail. @see: https://www.drupal.org/project/drupal/issues/2536370
       _serviceId: apigee_edge.sdk_connector
diff --git a/modules/apigee_edge_debug/src/SDKConnector.php b/modules/apigee_edge_debug/src/SDKConnector.php
index 3f736627..97043ccf 100644
--- a/modules/apigee_edge_debug/src/SDKConnector.php
+++ b/modules/apigee_edge_debug/src/SDKConnector.php
@@ -20,22 +20,19 @@
 
 namespace Drupal\apigee_edge_debug;
 
+use Apigee\Edge\ClientInterface;
 use Drupal\apigee_edge\SDKConnector as OriginalSDKConnector;
 use Drupal\apigee_edge\SDKConnectorInterface;
-use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Entity\EntityTypeManagerInterface;
-use Drupal\Core\Extension\InfoParserInterface;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\Http\ClientFactory;
-use Drupal\key\KeyRepositoryInterface;
+use Drupal\key\KeyInterface;
+use Http\Message\Authentication;
 
 /**
  * Service decorator for SDKConnector.
  */
-class SDKConnector extends OriginalSDKConnector implements SDKConnectorInterface {
+final class SDKConnector implements SDKConnectorInterface {
 
   /**
-   * Customer http request header.
+   * Custom HTTP request header.
    *
    * This tells the ApiClientProfiler to profile requests made by the underlying
    * HTTP client.
@@ -49,40 +46,60 @@ class SDKConnector extends OriginalSDKConnector implements SDKConnectorInterface
   /**
    * The inner SDK connector service.
    *
-   * @var \Drupal\apigee_edge\SDKConnector
+   * @var \Drupal\apigee_edge\SDKConnectorInterface
    */
   private $innerService;
 
+  /**
+   * The API client initialized from the saved credentials and default config.
+   *
+   * @var null|\Apigee\Edge\ClientInterface
+   *
+   * @see getClient()
+   */
+  private $defaultClient;
+
   /**
    * Constructs a new SDKConnector.
    *
    * @param \Drupal\apigee_edge\SDKConnectorInterface $inner_service
    *   The decorated SDK connector service.
-   * @param \Drupal\Core\Http\ClientFactory $client_factory
-   *   Http client.
-   * @param \Drupal\key\KeyRepositoryInterface $key_repository
-   *   The key repository.
-   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
-   *   Entity type manager service.
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The factory for configuration objects.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
-   *   Module handler service.
-   * @param \Drupal\Core\Extension\InfoParserInterface $info_parser
-   *   Info file parser service.
    */
-  public function __construct(SDKConnectorInterface $inner_service, ClientFactory $client_factory, KeyRepositoryInterface $key_repository, EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, InfoParserInterface $info_parser) {
+  public function __construct(SDKConnectorInterface $inner_service) {
     $this->innerService = $inner_service;
-    parent::__construct($client_factory, $key_repository, $entity_type_manager, $config_factory, $module_handler, $info_parser);
   }
 
   /**
    * {@inheritdoc}
    */
-  protected function httpClientConfiguration(): array {
-    $config = $this->innerService->httpClientConfiguration();
-    $config['headers'][static::HEADER] = static::HEADER;
-    return $config;
+  public function getOrganization(): string {
+    return $this->innerService->getOrganization();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getClient(?Authentication $authentication = NULL, ?string $endpoint = NULL, array $options = []): ClientInterface {
+    $extra_options[OriginalSDKConnector::CLIENT_FACTORY_OPTIONS]['headers'][static::HEADER] = static::HEADER;
+
+    // If method got called without default parameters, initialize and/or
+    // return the default API client from the internal cache.
+    if (!isset($authentication, $endpoint) && empty($options)) {
+      if ($this->defaultClient === NULL) {
+        $this->defaultClient = $this->innerService->getClient($authentication, $endpoint, $extra_options);
+      }
+
+      return $this->defaultClient;
+    }
+
+    return $this->innerService->getClient($authentication, $endpoint, array_merge($options, $extra_options));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function testConnection(KeyInterface $key = NULL): void {
+    $this->innerService->testConnection($key);
   }
 
 }
diff --git a/src/OauthAuthentication.php b/src/OauthAuthentication.php
index 17edb239..2ebdeb56 100644
--- a/src/OauthAuthentication.php
+++ b/src/OauthAuthentication.php
@@ -35,7 +35,7 @@ class OauthAuthentication extends Oauth {
   protected function authClient(): ClientInterface {
     /** @var \Drupal\apigee_edge\SDKConnectorInterface $sdk_connector */
     $sdk_connector = \Drupal::service('apigee_edge.sdk_connector');
-    return $sdk_connector->buildClient(new BasicAuth($this->clientId, $this->clientSecret), $this->auth_server);
+    return $sdk_connector->getClient(new BasicAuth($this->clientId, $this->clientSecret), $this->auth_server);
   }
 
 }
diff --git a/src/SDKConnector.php b/src/SDKConnector.php
index 0a2b8bbe..d9a601c8 100644
--- a/src/SDKConnector.php
+++ b/src/SDKConnector.php
@@ -26,8 +26,8 @@
 use Drupal\apigee_edge\Exception\AuthenticationKeyException;
 use Drupal\apigee_edge\Exception\AuthenticationKeyNotFoundException;
 use Drupal\apigee_edge\Plugin\EdgeKeyTypeInterface;
+use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Extension\InfoParserInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Http\ClientFactory;
@@ -39,63 +39,67 @@
 /**
  * Provides an Apigee Edge SDK connector.
  */
-class SDKConnector implements SDKConnectorInterface {
+final class SDKConnector implements SDKConnectorInterface {
 
   /**
-   * The client object.
+   * HTTP client configuration options for ClientFactory.
    *
-   * @var null|\Http\Client\HttpClient
+   * @param string
    */
-  private static $client = NULL;
+  public const CLIENT_FACTORY_OPTIONS = 'client_factory_options';
+
+  /**
+   * The API client initialized from the saved credentials and default config.
+   *
+   * @var null|\Apigee\Edge\ClientInterface
+   *
+   * @see getClient()
+   */
+  private $defaultClient;
 
   /**
    * The currently used credentials object.
    *
    * @var null|\Drupal\apigee_edge\CredentialsInterface
    */
-  private static $credentials = NULL;
+  private $credentials;
 
   /**
    * Custom user agent prefix.
    *
    * @var null|string
+   *
+   * @see userAgentPrefix()
    */
-  private static $userAgentPrefix = NULL;
+  private $userAgentPrefix;
 
   /**
    * The config factory.
    *
    * @var \Drupal\Core\Config\ConfigFactoryInterface
    */
-  protected $configFactory;
+  private $configFactory;
 
   /**
    * The key repository.
    *
    * @var \Drupal\key\KeyRepositoryInterface
    */
-  protected $keyRepository;
-
-  /**
-   * The entity type manager.
-   *
-   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
-   */
-  protected $entityTypeManager;
+  private $keyRepository;
 
   /**
    * The module handler service.
    *
    * @var \Drupal\Core\Extension\ModuleHandlerInterface
    */
-  protected $moduleHandler;
+  private $moduleHandler;
 
   /**
    * The info parser.
    *
    * @var \Drupal\Core\Extension\InfoParserInterface
    */
-  protected $infoParser;
+  private $infoParser;
 
   /**
    * The HTTP client factory.
@@ -111,8 +115,6 @@ class SDKConnector implements SDKConnectorInterface {
    *   Http client.
    * @param \Drupal\key\KeyRepositoryInterface $key_repository
    *   The key repository.
-   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
-   *   Entity type manager service.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The factory for configuration objects.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
@@ -120,66 +122,71 @@ class SDKConnector implements SDKConnectorInterface {
    * @param \Drupal\Core\Extension\InfoParserInterface $info_parser
    *   Info file parser service.
    */
-  public function __construct(ClientFactory $client_factory, KeyRepositoryInterface $key_repository, EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, InfoParserInterface $info_parser) {
+  public function __construct(ClientFactory $client_factory, KeyRepositoryInterface $key_repository, ConfigFactoryInterface $config_factory, ModuleHandlerInterface $module_handler, InfoParserInterface $info_parser) {
     $this->clientFactory = $client_factory;
-    $this->entityTypeManager = $entity_type_manager;
     $this->keyRepository = $key_repository;
     $this->configFactory = $config_factory;
     $this->moduleHandler = $module_handler;
     $this->infoParser = $info_parser;
   }
 
-  /**
-   * Get HTTP client overrides for Apigee Edge API client.
-   *
-   * Allows to override some configuration of the http client built by the
-   * factory for the API client.
-   *
-   * @return array
-   *   Associative array of configuration settings.
-   *
-   * @see http://docs.guzzlephp.org/en/stable/request-options.html
-   */
-  protected function httpClientConfiguration(): array {
-    return [
-      'connect_timeout' => $this->configFactory->get('apigee_edge.client')->get('http_client_connect_timeout') ?? 30,
-      'timeout' => $this->configFactory->get('apigee_edge.client')->get('http_client_timeout') ?? 30,
-      'proxy' => $this->configFactory->get('apigee_edge.client')->get('http_client_proxy') ?? '',
-    ];
-  }
-
   /**
    * {@inheritdoc}
    */
   public function getOrganization(): string {
-    $credentials = $this->getCredentials();
+    try {
+      $credentials = $this->getCredentials();
+    }
+    catch (AuthenticationKeyException $e) {
+      return '';
+    }
     return $credentials->getKeyType()->getOrganization($credentials->getKey());
   }
 
   /**
    * {@inheritdoc}
    */
-  public function getClient(?Authentication $authentication = NULL, ?string $endpoint = NULL): ClientInterface {
-    if ($authentication === NULL) {
-      if (self::$client === NULL) {
+  public function getClient(?Authentication $authentication = NULL, ?string $endpoint = NULL, array $options = []): ClientInterface {
+    // If method got called without default parameters, initialize and/or
+    // return the default API client from the internal cache.
+    if (!isset($authentication, $endpoint) && empty($options)) {
+      if ($this->defaultClient === NULL) {
         $credentials = $this->getCredentials();
-        /** @var \Drupal\apigee_edge\Plugin\EdgeKeyTypeInterface $key_type */
-        self::$client = $this->buildClient($credentials->getAuthentication(), $credentials->getKeyType()->getEndpoint($credentials->getKey()));
+        $this->defaultClient = $this->buildClient($credentials->getAuthentication(), $credentials->getKeyType()->getEndpoint($credentials->getKey()));
       }
 
-      return self::$client;
+      return $this->defaultClient;
     }
-    else {
-      return $this->buildClient($authentication, $endpoint);
+
+    // Fallback to the saved credentials.
+    if ($authentication === NULL) {
+      $credentials = $this->getCredentials();
+      $authentication = $credentials->getAuthentication();
     }
+
+    return $this->buildClient($authentication, $endpoint, $options);
   }
 
   /**
    * {@inheritdoc}
    */
-  public function buildClient(Authentication $authentication, ?string $endpoint = NULL, array $options = []): ClientInterface {
+  private function buildClient(Authentication $authentication, ?string $endpoint = NULL, array $options = []): ClientInterface {
+    $default_client_options = [
+      'connect_timeout' => $this->configFactory->get('apigee_edge.client')->get('http_client_connect_timeout') ?? 30,
+      'timeout' => $this->configFactory->get('apigee_edge.client')->get('http_client_timeout') ?? 30,
+      'proxy' => $this->configFactory->get('apigee_edge.client')->get('http_client_proxy') ?? '',
+    ];
+    if (isset($options[static::CLIENT_FACTORY_OPTIONS])) {
+      $http_client_options = NestedArray::mergeDeep($default_client_options, $options[static::CLIENT_FACTORY_OPTIONS]);
+      unset($options[static::CLIENT_FACTORY_OPTIONS]);
+    }
+    else {
+      $http_client_options = $default_client_options;
+    }
+
+    // Builder and user-agent prefix can not be overridden.
     $options += [
-      Client::CONFIG_HTTP_CLIENT_BUILDER => new Builder(new GuzzleClientAdapter($this->clientFactory->fromOptions($this->httpClientConfiguration()))),
+      Client::CONFIG_HTTP_CLIENT_BUILDER => new Builder(new GuzzleClientAdapter($this->clientFactory->fromOptions($http_client_options))),
       Client::CONFIG_USER_AGENT_PREFIX => $this->userAgentPrefix(),
     ];
     return new Client($authentication, $endpoint, $options);
@@ -192,30 +199,19 @@ public function buildClient(Authentication $authentication, ?string $endpoint =
    *   The key entity.
    */
   private function getCredentials(): CredentialsInterface {
-    if (self::$credentials === NULL) {
+    if ($this->credentials === NULL) {
       $active_key = $this->configFactory->get('apigee_edge.auth')->get('active_key');
       if (empty($active_key)) {
         throw new AuthenticationKeyException('Apigee Edge API authentication key is not set.');
       }
-      if (!($key = $this->keyRepository->getKey($active_key))) {
+      $key = $this->keyRepository->getKey($active_key);
+      if (!$key) {
         throw new AuthenticationKeyNotFoundException($active_key, 'Apigee Edge API authentication key not found with "@id" id.');
       }
-      self::$credentials = $this->buildCredentials($key);
+      $this->credentials = $this->buildCredentials($key);
     }
 
-    return self::$credentials;
-  }
-
-  /**
-   * Changes credentials used by the API client.
-   *
-   * @param \Drupal\apigee_edge\CredentialsInterface $credentials
-   *   The new credentials object.
-   */
-  private function setCredentials(CredentialsInterface $credentials) {
-    self::$credentials = $credentials;
-    // Ensure that client will be rebuilt with the new key.
-    self::$client = NULL;
+    return $this->credentials;
   }
 
   /**
@@ -228,47 +224,45 @@ private function setCredentials(CredentialsInterface $credentials) {
    *   The credentials.
    */
   private function buildCredentials(KeyInterface $key): CredentialsInterface {
-    /** @var \Drupal\apigee_edge\Plugin\EdgeKeyTypeInterface $key */
     if ($key->getKeyType() instanceof EdgeKeyTypeInterface) {
       if ($key->getKeyType()->getAuthenticationType($key) === EdgeKeyTypeInterface::EDGE_AUTH_TYPE_OAUTH) {
         return new OauthCredentials($key);
       }
       return new Credentials($key);
     }
-    else {
-      throw new AuthenticationKeyException("Type of {$key->id()} key does not implement EdgeKeyTypeInterface.");
-    }
+
+    throw new AuthenticationKeyException("Type of {$key->id()} key does not implement EdgeKeyTypeInterface.");
   }
 
   /**
    * Generates a custom user agent prefix.
    */
-  protected function userAgentPrefix(): string {
-    if (NULL === self::$userAgentPrefix) {
+  private function userAgentPrefix(): string {
+    if ($this->userAgentPrefix === NULL) {
       $module_info = $this->infoParser->parse($this->moduleHandler->getModule('apigee_edge')->getPathname());
       if (!isset($module_info['version'])) {
         $module_info['version'] = '8.x-1.x-dev';
       }
       // TODO Change "DevPortal" to "Drupal module" later. It has been added for
       // Apigee's convenience this way.
-      self::$userAgentPrefix = $module_info['name'] . ' DevPortal ' . $module_info['version'];
+      $this->userAgentPrefix = $module_info['name'] . ' DevPortal ' . $module_info['version'];
     }
 
-    return self::$userAgentPrefix;
+    return $this->userAgentPrefix;
   }
 
   /**
    * {@inheritdoc}
    */
-  public function testConnection(KeyInterface $key = NULL) {
-    if ($key !== NULL) {
-      $credentials = $this->buildCredentials($key);
-      $client = $this->buildClient($credentials->getAuthentication(), $credentials->getKeyType()->getEndpoint($credentials->getKey()));
-    }
-    else {
+  public function testConnection(KeyInterface $key = NULL): void {
+    if ($key === NULL) {
       $client = $this->getClient();
       $credentials = $this->getCredentials();
     }
+    else {
+      $credentials = $this->buildCredentials($key);
+      $client = $this->buildClient($credentials->getAuthentication(), $credentials->getKeyType()->getEndpoint($credentials->getKey()));
+    }
 
     try {
       // We use the original, non-decorated organization controller here.
@@ -276,12 +270,7 @@ public function testConnection(KeyInterface $key = NULL) {
       $oc->load($credentials->getKeyType()->getOrganization($credentials->getKey()));
     }
     catch (\Exception $e) {
-      throw $e;
-    }
-    finally {
-      if (isset($original_credentials)) {
-        self::$credentials = $this->setCredentials($original_credentials);
-      }
+      throw new AuthenticationKeyException($e->getMessage(), $e->getCode(), $e);
     }
   }
 
diff --git a/src/SDKConnectorInterface.php b/src/SDKConnectorInterface.php
index 61e2fadf..d8d84df2 100644
--- a/src/SDKConnectorInterface.php
+++ b/src/SDKConnectorInterface.php
@@ -29,45 +29,43 @@
 interface SDKConnectorInterface {
 
   /**
-   * Gets the organization.
+   * Gets the organization used by the API client.
    *
    * @return string
-   *   The organization.
+   *   The organization or an empty string if the Apigee Edge authentication
+   *   key has not been saved yet.
    */
   public function getOrganization(): string;
 
   /**
-   * Returns the http client.
+   * Returns a pre-configured API client.
+   *
+   * @param null|\Http\Message\Authentication $authentication
+   *   The authentication method, default is retrieved from the active key.
+   * @param null|string $endpoint
+   *   API endpoint, default is https://api.enterprise.apigee.com/v1.
+   * @param array $options
+   *   The API Client configuration options.
    *
    * @return \Apigee\Edge\ClientInterface
-   *   The http client.
+   *   The API client.
+   *
+   * @throws \Drupal\apigee_edge\Exception\AuthenticationKeyException
+   *   If the API client could not be built, ex.: missing Apigee Edge
+   *   authentication key.
    */
-  public function getClient(): ClientInterface;
+  public function getClient(?Authentication $authentication = NULL, ?string $endpoint = NULL, array $options = []): ClientInterface;
 
   /**
    * Test connection with the Edge Management Server.
    *
    * @param \Drupal\key\KeyInterface|null $key
-   *   Key entity to check connection with Edge,
-   *   if NULL, then use the stored key.
-   *
-   * @throws \Exception
-   */
-  public function testConnection(KeyInterface $key = NULL);
-
-  /**
-   * Returns a pre-configured API client with the provided credentials.
+   *   Key entity with Apigee Edge credentials or NULL if the saved key should
+   *   be used.
    *
-   * @param \Http\Message\Authentication $authentication
-   *   Authentication.
-   * @param null|string $endpoint
-   *   API endpoint, default is https://api.enterprise.apigee.com/v1.
-   * @param array $options
-   *   Client configuration option.
-   *
-   * @return \Apigee\Edge\ClientInterface
-   *   Configured API client.
+   * @throws \Drupal\apigee_edge\Exception\AuthenticationKeyException
+   *   If the authentication fails with the saved- or provided key.
    */
-  public function buildClient(Authentication $authentication, ?string $endpoint = NULL, array $options = []): ClientInterface;
+  public function testConnection(KeyInterface $key = NULL): void;
 
 }
diff --git a/tests/modules/apigee_edge_test/apigee_edge_test.services.yml b/tests/modules/apigee_edge_test/apigee_edge_test.services.yml
index 92cab64d..a40fbd34 100644
--- a/tests/modules/apigee_edge_test/apigee_edge_test.services.yml
+++ b/tests/modules/apigee_edge_test/apigee_edge_test.services.yml
@@ -22,7 +22,7 @@ services:
     decorates: apigee_edge_debug.sdk_connector
     decoration_priority: 0
     public: false
-    arguments: ['@apigee_edge_test.sdk_connector.inner', '@logger.channel.apigee_edge_test', '@http_client_factory', '@key.repository', '@entity_type.manager', '@config.factory', '@module_handler', '@info_parser']
+    arguments: ['@apigee_edge_test.sdk_connector.inner', '@logger.channel.apigee_edge_test']
     properties:
       # Without this property for decorated services, serialization will fail. @see: https://www.drupal.org/project/drupal/issues/2536370
       _serviceId: apigee_edge.sdk_connector
diff --git a/tests/modules/apigee_edge_test/src/SDKConnector.php b/tests/modules/apigee_edge_test/src/SDKConnector.php
index df6be696..8a400d4b 100644
--- a/tests/modules/apigee_edge_test/src/SDKConnector.php
+++ b/tests/modules/apigee_edge_test/src/SDKConnector.php
@@ -23,68 +23,88 @@
 use Apigee\Edge\Client;
 use Apigee\Edge\ClientInterface;
 use Apigee\Edge\Exception\ApiResponseException;
-use Drupal\apigee_edge\SDKConnector as DecoratedSDKConnector;
 use Drupal\apigee_edge\SDKConnectorInterface;
-use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Entity\EntityTypeManagerInterface;
-use Drupal\Core\Extension\InfoParserInterface;
-use Drupal\Core\Extension\ModuleHandlerInterface;
-use Drupal\Core\Http\ClientFactory;
-use Drupal\Core\Logger\LoggerChannelInterface;
-use Drupal\key\KeyRepositoryInterface;
+use Drupal\key\KeyInterface;
 use Http\Client\Exception;
 use Http\Message\Authentication;
 use Psr\Http\Message\RequestInterface;
+use Psr\Log\LoggerInterface;
 
 /**
  * Service decorator for SDKConnector.
  */
-final class SDKConnector extends DecoratedSDKConnector implements SDKConnectorInterface {
+final class SDKConnector implements SDKConnectorInterface {
 
   /**
    * The decorated SDK connector service.
    *
-   * @var \Drupal\apigee_edge\SDKConnector
+   * @var \Drupal\apigee_edge\SDKConnectorInterface
    */
   private $innerService;
 
   /**
    * A logger instance.
    *
-   * @var \Drupal\Core\Logger\LoggerChannelInterface
+   * @var \Psr\Log\LoggerInterface
    */
   private $logger;
 
+  /**
+   * The API client initialized from the saved credentials and default config.
+   *
+   * @var null|\Apigee\Edge\ClientInterface
+   *
+   * @see getClient()
+   */
+  private $defaultClient;
+
   /**
    * Constructs a new SDKConnector.
    *
    * @param \Drupal\apigee_edge\SDKConnectorInterface $inner_service
    *   The decorated SDK connector service.
-   * @param \Drupal\Core\Logger\LoggerChannelInterface $logger
-   *   Logger interface.
-   * @param \Drupal\Core\Http\ClientFactory $clientFactory
-   *   Http client.
-   * @param \Drupal\key\KeyRepositoryInterface $key_repository
-   *   The key repository.
-   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
-   *   Entity type manager service.
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The factory for configuration objects.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
-   *   Module handler service.
-   * @param \Drupal\Core\Extension\InfoParserInterface $infoParser
-   *   Info file parser service.
+   * @param \Psr\Log\LoggerInterface $logger
+   *   The logger.
    */
-  public function __construct(SDKConnectorInterface $inner_service, LoggerChannelInterface $logger, ClientFactory $clientFactory, KeyRepositoryInterface $key_repository, EntityTypeManagerInterface $entity_type_manager, ConfigFactoryInterface $config_factory, ModuleHandlerInterface $moduleHandler, InfoParserInterface $infoParser) {
+  public function __construct(SDKConnectorInterface $inner_service, LoggerInterface $logger) {
     $this->innerService = $inner_service;
     $this->logger = $logger;
-    parent::__construct($clientFactory, $key_repository, $entity_type_manager, $config_factory, $moduleHandler, $infoParser);
   }
 
   /**
    * {@inheritdoc}
    */
-  public function buildClient(Authentication $authentication, ?string $endpoint = NULL, array $options = []): ClientInterface {
+  public function getOrganization(): string {
+    return $this->innerService->getOrganization();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getClient(?Authentication $authentication = NULL, ?string $endpoint = NULL, array $options = []): ClientInterface {
+    // If method got called without default parameters, initialize and/or
+    // return the default API client from the internal cache.
+    if (!isset($authentication, $endpoint) && empty($options)) {
+      if ($this->defaultClient === NULL) {
+        $this->defaultClient = $this->innerService->getClient($authentication, $endpoint, $this->getOptionsWithRetryPlugin($options));
+      }
+
+      return $this->defaultClient;
+    }
+
+    return $this->innerService->getClient($authentication, $endpoint, $this->getOptionsWithRetryPlugin($options));
+  }
+
+  /**
+   * Returns the options array with the retry decider plugin.
+   *
+   * @param array $options
+   *   Array if API client options.
+   *
+   * @return array
+   *   Array of API client options.
+   */
+  private function getOptionsWithRetryPlugin(array $options): array {
     $decider = function (RequestInterface $request, Exception $e) {
       // Only retry API calls that failed with this specific error.
       if ($e instanceof ApiResponseException && $e->getEdgeErrorCode() === 'messaging.adaptors.http.flow.ApplicationNotFound') {
@@ -99,11 +119,11 @@ public function buildClient(Authentication $authentication, ?string $endpoint =
       return FALSE;
     };
     // Use the retry plugin in tests.
-    return $this->innerService->buildClient($authentication, $endpoint, [
+    return array_merge($options, [
       Client::CONFIG_RETRY_PLUGIN_CONFIG => [
         'retries' => 5,
         'exception_decider' => $decider,
-        'exception_delay' => function (RequestInterface $request, Exception $e, $retries) : int {
+        'exception_delay' => static function (RequestInterface $request, Exception $e, $retries) : int {
           return $retries * 15000000;
         },
       ],
@@ -113,8 +133,8 @@ public function buildClient(Authentication $authentication, ?string $endpoint =
   /**
    * {@inheritdoc}
    */
-  protected function httpClientConfiguration(): array {
-    return $this->innerService->httpClientConfiguration();
+  public function testConnection(KeyInterface $key = NULL): void {
+    $this->innerService->testConnection($key);
   }
 
 }